8iol
The complex of Rubisco large subunit (RbcL)
Structural highlights
FunctionRBL_SYNP6 RuBisCO catalyzes two reactions: the carboxylation of D-ribulose 1,5-bisphosphate, the primary event in carbon dioxide fixation, as well as the oxidative fragmentation of the pentose substrate in the photorespiration process. Both reactions occur simultaneously and in competition at the same active site.[HAMAP-Rule:MF_01338] Publication Abstract from PubMedHexadecameric form I Rubisco, which consisting consists of eight large (RbcL) and eight small (RbcS) subunits, is the most abundant enzyme on earth. Extensive efforts to engineer an improved Rubisco to speed up its catalytic efficiency and ultimately increase agricultural productivity. However, difficulties with correct folding and assembly in foreign hosts or in vitro have hampered the genetic manipulation of hexadecameric Rubisco. In this study, we reconstituted Synechococcus sp. PCC6301 Rubisco in vitro using the chaperonin system and assembly factors from cyanobacteria and Arabidopsis thaliana (At). Rubisco holoenzyme was produced in the presence of cyanobacterial Rubisco accumulation factor 1 (Raf1) alone or both AtRaf1 and bundle-sheath defective-2 (AtBsd2) from Arabidopsis. RbcL released from GroEL is assembly capable in the presence of ATP, and AtBsd2 functions downstream of AtRaf1. Cryo-EM structures of RbcL(8)-AtRaf1(8), RbcL(8)-AtRaf1(4)-AtBsd2(8), and RbcL(8) revealed that the interactions between RbcL and AtRaf1 are looser than those between prokaryotic RbcL and Raf1, with AtRaf1 tilting 7 degrees farther away from RbcL. AtBsd2 stabilizes the flexible regions of RbcL, including the N and C termini, the 60s loop, and loop 6. Using these data, combined with previous findings, we propose the possible biogenesis pathways of prokaryotic and eukaryotic Rubisco. Structural insights into the functions of Raf1 and Bsd2 in hexadecameric Rubisco assembly.,Wang R, Song H, Zhang W, Wang N, Zhang S, Shao R, Liu C Mol Plant. 2023 Dec 4;16(12):1927-1936. doi: 10.1016/j.molp.2023.10.011. Epub , 2023 Oct 17. PMID:37853692[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
| ||||||||||||||||||
